Core B, that was favorably received and budget approved, will provide all human airway smooth muscle (HASM) cell lines, precision cut lung slice (PCLS) studies and magnetic twisting cytometry (MTC) measurements of single ASM force generation that will be used in the research projects. Our laboratory has 20 years of experience in the establishment, cultivation and characterization of HASM cells. Core B will provide and develop novel platforms to measure bronchoconstriction and bronchodilation in HASM cells using MTC and in human small ainways using human PCLS (hPCLS) to characterize E-C signal transduction processes. Quality assurance and characterization of cell lines will be performed using our established approaches. The use of ASM cell lines derived coincident with hPCLS provides a unique cell- and tissue- based platform that enables investigators to molecular dissect the contribution of specific cell signaling events in the regulation of physiologically relevant ex vivo outcomes. The aims of this facility core will meet the anticipated needs of the four interactive projects. In Project 1, PCLS will sen/e as a useful model in the characterization of B2-adrenergic receptor (B2AR) desensitization in HASM cells from non-asthma and fatal asthma subjects and will provide an opportunity to molecularly dissect critical signaling pathways by which steroids modulate B2AR tachyphylaxis. In Project 2, HASM cells will be used to characterize taste receptor- mediated inhibition of ASM contraction and desensitization regarding the taste receptor ligands. In Project 3, HASM cell lines and hPCLS will be used to determine the role of proton-activated GPCR regulation of the contractile responses as measured by twisting cell microscopy or calcium mobilization studies performed in HASM cells and by bronchoconstriction in PCLS. In Project 4, HASM cell lines and hPCLS will be used to define novel approaches to inhibit B2AR desensitization and Gq-mediated contractile responses. A centralized human cell and tissue core with faculty and research staff adept in the manipulation of HASM cells is a unique asset that ensures success and provides advantages with regard to centralized quality assurance across the Program Project grant. RELEVANCE (See instructions): Core B will provide human cells and tissue for the Program Project Grant in order to characterize molecular mechanisms regulating bronchoconstriction and bronchodilation.